Question: Who is the spouse of Lord Byron as of January 1st 1815?
Paraphrase: Lord Byron's wife in January 1st 1985?
SPARQL (Wikidata): SELECT ?obj WHERE { wd:Q5679 p:P26 ?s . ?s ps:P26 ?obj . ?s pq:P580 ?x filter(contains(YEAR(?x),'1815')) }